builtin-update-ref.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "builtin.h"
   4
   5 static const char git_update_ref_usage[] =
   6 "git-update-ref <refname> <value> [<oldval>] [-m <reason>]";
   7
   8 int cmd_update_ref(int argc, const char **argv, char **envp)
   9 {
  10         const char *refname=NULL, *value=NULL, *oldval=NULL, *msg=NULL;
  11         struct ref_lock *lock;
  12         unsigned char sha1[20], oldsha1[20];
  13         int i;
  14
  15         setup_ident();
  16         setup_git_directory();
  17         git_config(git_default_config);
  18
  19         for (i = 1; i < argc; i++) {
  20                 if (!strcmp("-m", argv[i])) {
  21                         if (i+1 >= argc)
  22                                 usage(git_update_ref_usage);
  23                         msg = argv[++i];
  24                         if (!*msg)
  25                                 die("Refusing to perform update with empty message.");
  26                         if (strchr(msg, '\n'))
  27                                 die("Refusing to perform update with \\n in message.");
  28                         continue;
  29                 }
  30                 if (!refname) {
  31                         refname = argv[i];
  32                         continue;
  33                 }
  34                 if (!value) {
  35                         value = argv[i];
  36                         continue;
  37                 }
  38                 if (!oldval) {
  39                         oldval = argv[i];
  40                         continue;
  41                 }
  42         }
  43         if (!refname || !value)
  44                 usage(git_update_ref_usage);
  45
  46         if (get_sha1(value, sha1))
  47                 die("%s: not a valid SHA1", value);
  48         memset(oldsha1, 0, 20);
  49         if (oldval && get_sha1(oldval, oldsha1))
  50                 die("%s: not a valid old SHA1", oldval);
  51
  52         lock = lock_any_ref_for_update(refname, oldval ? oldsha1 : NULL, 0);
  53         if (!lock)
  54                 return 1;
  55         if (write_ref_sha1(lock, sha1, msg) < 0)
  56                 return 1;
  57
  58         /* write_ref_sha1 always unlocks the ref, no need to do it explicitly */
  59         return 0;
  60 }